The Collaborative International Dictionary of English v.0.48:
Stirrup \Stir"rup\, n. [OE. stirop, AS. stigr[=a]p; st[imac]gan
to mount, ascend + r[=a]p a rope; akin to G. stegreif a
stirrup. [root]164. See Sty, v. i., and Rope.]
1. A kind of ring, or bent piece of metal, wood, leather, or
the like, horizontal in one part for receiving the foot of
a rider, and attached by a strap to the saddle, -- used to
assist a person in mounting a horse, and to enable him to
sit steadily in riding, as well as to relieve him by
supporting a part of the weight of the body.
Our host upon his stirpoes stood anon. --Chaucer.
2. (Carp. & Mach.) Any piece resembling in shape the stirrup
of a saddle, and used as a support, clamp, etc. See
3. (Naut.) A rope secured to a yard, with a thimble in its
lower end for supporting a footrope. --Totten.
Stirrup bone (Anat.), the stapes.
Stirrup cup, a parting cup taken after mounting.
Stirrup iron, an iron stirrup.
Stirrup leather, or Stirrup strap, the strap which
attaches a stirrup to the saddle. See Stirrup, 1.